*{
  margin: 0;
  padding: 0;
  list-style: none;
  box-sizing: border-box;
}
span{
  margin-left: 20px;
}
.on{
  background: #f0f;
}
button{
  padding: 5px;
  border: none;
}
a{
  margin-left: 50px;
}
.active{
  color: #f0f;
}